Change function definition based on condition

I am trying to define a conditional function that is the definition of the function depends on the input value. I also want it to run on several different inputs contained in a list.

The output that I am getting is not what I am expecting. For the following inputs: incomes = [500, 1500, 4000] I expect the output to be: 50, 200 but the actual outputs are: -150, 150 and 900 respectively. The outputs that I was expecting are: . I do get the correct output when I enter only one income value to the list.

incomes = [500, 1500, 4000]
for current_income in incomes:
    income = current_income
    if income <1000:
        def tax(income):
            return income*0.1
    elif 1000<=income<2000:
        def tax(income):
            return 1000*0.1 +(income-1000)*0.2
    else:
        def tax(income):
         return 1000*0.1+ 1000*0.2 + (income-2000)*0.3

for i in incomes:
    result = tax(i)
    print(result)

It seems that the order of values in the list matter : I reversed the order of incomes in the list I get the output of: 400, 150, 50. I understand that the problem lies in the interaction of the for loop and if, elsif and else conditions but I do not see what is actually wrong in my code.